Former foreign secretary David Miliband accused Mr Cameron of being a "loudmouth" over the remarks but his current counterpart instead praise the Prime Minister's "plain speaking".

Mr Cameron's remarks came during a question and answer session following a speech in Bangalore, after he was asked by a member of the audience why the UK was pouring money into Pakistan, given reports that it was linked to the 2008 Mumbai terrorist attacks.

Mr Cameron said: “We can not tolerate in any sense the idea that this country is allowed to look both ways and is able, in any way, to promote the export of terror, whether to India or whether to Afghanistan or anywhere else in the world.

"It should be a relationship based on a very clear message: that it is not right to have any relationship with groups that are promoting terror.

“Democratic states that want to be part of the developed world can not do that."

Pakistan responded with alarm to Mr Cameron’s words. Abdul Basit, spokesman for the Pakistan Foreign Ministry, said: "Pakistan is fully committed against militancy and terrorism anywhere in the world as we ourselves are victims of this hydra-headed menace."